It is fashionable to drive a car, but to drive a car is not nearly as difficult as it is imagined on condition that you ______ the specialized rules.
An increasing number of people ________ the importance to physical exercise.
—Who______ it be that is knocking at the door? —It ______ be Father, but I’m not sure.
The teacher will never have Tom away within the exam.
The two sisters are ________ different in character --- one talks a lot while the other is a girl of few words.
He has been in bed ______ he fell off his bike a week ago.